Pulse radiolysis in water with heavy-ion beams. A short review

Experimental investigation of picosecond dynamics following interactions between laser accelerated protons and water

“…The image has been truncated from the full ns-duration of the probe pulse for clarity. (b) Model of absorbance in (a) based on the extrapolation of expected yields 6,8 (approximately 4 solvated electrons per 100 eV of deposited energy, decreasing with increasing linear energy transfer) and decay kinetics 19,20 of solvated electrons from studies with lower dose rates and measured at similar or longer times. The initial, exponentially decaying, proton energy spectrum is assumed to be similar to what was recorded during the experiment with a maximum proton energy of $10 MeV.…”

“…The diamonds mark expected absorbance according to the model displayed in Fig. 2(b), based on the extrapolation of the yields of solvated electrons from publications 6,8 with lower dose rates. The error bars take into account the shot-to-shot fluctuations in the proton energy spectra, in terms of both maximum energy and the number of protons for each energy.…”

“…For picosecond time scales, however, this method becomes less reliable due to the very high concentration of scavengers needed. Traditionally, such experiments were performed in combination with Monte Carlo simulations 7,8 to study the early effects of the high energy protons on water.…”

Concentration and Incident Energy Dependences of Transient Species in Water by H⁺ Ion Irradiation

“…The characteristic effects have been investigated by using water and aqueous solutions in the past because water is considerable substance of the radiation biology. There are two methods to clarify reactions of the reactive species; the scavenging method [1][2][3] and the time-resolved spectroscopic method [4][5][6][7]. The scavenging method has been used to estimate the yields of the reactive species in water samples irradiated with heavy ions.…”

“…The scavenging method is widely accepted for the estimation of radical yield because the scavengers used in these studies react only with the individual radicals and the products are stable. By contrast, the pulse radiolysis can observe reactions of the reactive species directly by using spectroscopy methods [4]. Baldacchino et al succeeded in construction of the time resolved measurement system using pulsed high-energy heavy ion beams at GANIL (Grand Accelerateur National d'Ions Lourds) facility, and estimated the yields of the OH radical produced by 975 MeV C 6+ ion irradiation [5].…”